Shoe sole provided with transpiration aid avoiding the inlet of liquids from the outside

ABSTRACT

A shoe comprising a sole with a plurality of check valves provided for discharging air from the inside of the shoe. The check valve having a microhole and a concave zone wherein the air is forced out the bottom of the shoe sole through the valves upon pressure exerted by the wearer.

This application is a 371 of PCT/IT98/00090 filed on Apr. 17, 1998.

FIELD OF THE INVENTION

The present invention relates to a sole for any type of shoes,particularly a sole made, for example, of moulded rubber, characterizedin that its construction is such as to guarantee an effectivetranspiration of the foot and to be impermeable to water and humidity.

BACKGROUND OF THE INVENTION

Especially in case of shoes provided with a rubber sole it is extremelyimportant to ensure an effective ventilation of the foot in order toavoid that an excessive perspiration causes the sweat to impregnate thefixed insole in contact with the skin of the foot and to produceannoying damages such as reddening of the skin, sores, etc., besides badsmell.

On the other hand many shoes with leather sole are not devoid of such atrouble.

In order to overcome such a problem a number of solutions have beenbrought forward, among which a recent one has been described in ItalianPatent No. 1,232,798, available on the market with the name GEOX(registered trademark). Such a solution provides an osmotic membraneplaced in the rubber sole and communicating with the inside of the shoethrough holes in the fixed insole and with the outside through holes inthe tread. As a result, the sole is made to transpire, though it staysimpermeable to humidity. Although the membrane is protected by suitablelayers of inert, transpiring material and it stands the mechanicalstress due to the extension and torsions caused by the movement duringwalking, such a solution does not provide suitable guarantees ofdurability for the shoe as it requires strict maintenance conditionswhich cannot be easily kept up. One example is that the shoe must not bedried by heat sources so as not to damage the membrane.

SUMMARY OF THE INVENTION

The present invention seeks to provide a solution to the problem oftranspiration, for example, of a rubber sole or a leather sole, keepingthe impermeability unchanged without using membranes made of specialmaterial and as such needing particular care, but only providing withinthe width of the sole a plurality of air discharging valves of resilientmaterial provided with microholes establishing a communication betweenthe inside and the outside of the shoe and acting as check valves.Advantageously, in case of rubber soles, such valves are preferably onepiece and made in one moulding step along with the sole, and essentiallyconsist of a membrane provided with a cavity directed towards the fixedsole on its upper side and with a hollow space or a chamber whichcommunicates with the tread and then with the outside on its lower side.Such a chamber is capable of protecting the membrane from any type ofatmospheric agent.

The microhole of each valve is made in the membrane at the centre of itsconcavity.

According to another feature of the invention, the microhole is piercedthrough the membrane during a machining step following the moulding ofthe sole which is processed again to mechanically pierce the membrane byneedles or stings. It should be appreciated that in such a way the holepierced through the membrane will never result to be fully regular as itwould be the case if the hole was pierced during the moulding step, butit looks much like a tearing so that the membrane can perfectly pluginto it.

Such a combination of measures during walking causes the user's weightto increase the air pressure in the chambers so as to oppose to theconcavity of the membrane, following the deflection and the resilientdeformation of the chambers located in the area in contact with theground. Thus the hole inside the membrane closes and prevents outsidefluids from entering the shoe. On the other hand, when the pressureinside the membrane is greater than the pressure in the outer chamber,the hole inside the concave membrane is opened causing the release ofthe inner air until the inside pressure coincides with the outsidepressure.

Number and distribution of the valves in the sole may obviously bedifferent according to the circumstances. Sometimes only a few valveslocated in suitable zones of the tread, for example near the heel or inthree zones of the foot sole corresponding to toes, arch, and heel, etc.may be provided.

As an alternative, rather than having the valves of resilient materialmade in one piece with the sole during one moulding step, they may beinserted through holes made at crucial spots of the sole.

Further advantages and features of the invention will be more readilyapparent from the following detailed description with reference to theaccompanying drawings which show only by way of a not limiting examplesome preferred embodiments. In the drawings:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a shoe during walking with a soleprovided with discharge valves according to the present invention, fromwhich the perforated fixed insole has been fully removed and the leftside of the vamp has been partially removed in order to show the way thevalves are arranged on the upper portion of the sole;

FIGS. 2 to 4 show a sectioned view of some embodiments of the dischargevalve;

FIGS. 5 an 6 show another embodiment which provides a perforatedigloo-shaped dome above the discharge valve;

FIGS. 7 and 8 show a section view and a plan view, respectively, of anembodiment of the invention which provides studs all around the valve;

FIG. 9 is a plan view of the sole from the insole side and shows the waythe valves are arranged according to the embodiment of FIGS. 5 and 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the figures, the functioning of the check valve forthe discharge of inside air can be referred to that of ordinary rubberor latex valves, for example, used in catheter and comprising a membranewith reduced thickness provided with an upward pointing concavity whichcloses a tubular conduit connected to an inflatable bladder. Afterpiercing the membrane and blowing air therein, the bladder will inflateand remain swollen as the pressure acting on the membrane itself willclose the microhole through which air had passed just thanks to theconcavity of the membrane.

Turning now to FIG. 2, it is shown therein a partial section of a sole 2(preferably made of rubber or leather, most preferably rubber) providedwith a discharge valve according to a first embodiment of the invention.As it can be seen, the valve encircled by an oval frame for a betterillustration is made during one moulding step in one piece with sole 2(though it can instead be later inserted into moulded sole 2) andessentially includes a membrane 4 with reduced thickness which limits aconcave zone 1 at the upper side. Such a zone has preferably, but notnecessarily, a circular plan. Even the lower surface of the membrane,indicated at 5, is slightly curved with the concavity directed upwards.Such a surface is the ceiling of a hollow space, cell or chamber 9 whichcommunicates with road surface 8 through orifice 6.

Such orifice can be more or less wide (compare the reduced dimension ofthe orifice of FIG. 2 with that of the orifice of FIG. 3, where chamber9 is fully open towards tread 8).

According to the present invention a through microhole 14 is piercedinside membrane 4. Such a microhole is preferably pierced at its centreand has such a dimension as to be only open when the pressure on thetread side is lower than the inside pressure. The operation isschematically illustrated in FIG. 1. During walking, as with an increasein the user's weight the concavity of the membrane concurrentlyincreases opening the holes, in contrast to that there does occur apressure increase inside chambers 9′ over the area of maximum contactwith the ground, which will cause membrane 4 to be compressed from belowand consequently the holes of all of the corresponding valves to beclosed. As it can be seen from the figure, chambers 9 of the othervalves not lying along the vertical weight pressure vector aredecompressed, thus causing the air inside the shoe to easily escape.FIGS. 3 to 6 show a number of valves different from one another in termsof the shape of chamber 9 (FIGS. 2, 3, 4) and/or for the presence of acurved lip 10 projecting along the periphery of upper concavity 1 (FIGS.5 and 6). Such lip defines a dome-shaped chamber 12 or an igloo whichcommunicates with the outside through a central hole 11 at its top.Since such a dome or igloo 12 directly contacts the fixed insole duringthe dynamics of walking, it acts as a pump just thanks to itsdeformation and following resilient return that causes air inside theshoe to be forcibly expelled through the hole in the underlying membraneoperating as a check valve during walking and with repeated, cycles ofloading onto and unloading from the sole of the user's weight. Inaddition, such a dome or igloo exerts a real massaging action on thefoot.

FIGS. 7 and 8 show another embodiment of the invention which providesstuds 7 distributed all around hole 6 of chamber 9. Such studs have thefunction of breaking the liquid film on the road after a shower avoidingthe aqua planing effects.

FIG. 9 shows a typical distribution of the valves in three significantareas of the sole. The illustrated embodiment is that of FIGS. 5 and 6with a circular lip 10 and a central hole 11.

It is self-evident that the embodiment of FIGS. 5 and 6, i.e. that withigloos, the distribution of the igloos on the upper surface of the soleshould be such as to ensure an even bearing of the fixed insole whichshould not be affected, of course, by the presence of uncomfortablerelief on the ground. On the other hand, it is not necessary that acheck valve corresponds to each igloo. Their number can be limited withregard to that of igloos so as to be only provided in the most suitablespots.

It is evident that as an alternative to the valves made in one piece andone moulding step along with the sole, as described so far, the use ofvalves inserted in the sole may be provided. Particularly such valvescan be made with materials having a specific weight different from thatof the sole so as to combine their resilient features with those of thesole in the best possible way in order to reach the desired objectives.It should be taken into consideration, for example, the case of aleather sole.

These and other changes which can be made by those skilled in the artare to be considered in the scope of the present invention as defined inthe appended claims.

What is claimed is:
 1. A shoe having therein a shoe sole in which thereare provided a plurality of check valves for discharging air containedin an inside of the shoe said check valves being made of a resilientmaterial and each provided with a microhole connecting the inside of theshoe with an outside, such valves being formed of a membrane providedwith a concavity that has a concave surface directed towards a fixedinsole inside said shoe and beneath which a hollow space or chamber isformed which communicates through a lower side of the membrane with theoutside and a tread of the shoe.
 2. The shoe sole of claim 1, whereinthe microhole of each valve is pierced at the centre of its concavity.3. The shoe sole of claim 1, wherein said concave membrane has acircular plan.
 4. The shoe sole of claim 1, wherein said fixed insole isperforated and wherein even the lower side of the membrane is slightlycurved with a concavity directed upwards at the perforated fixed insole,and wherein said lower side of the membrane forms a ceiling of thechamber.
 5. The shoe sole of claim 1, wherein the membrane has athickness which is essentially smaller that the thickness of the sole.6. The shoe of claim 1, wherein, during walking, when a pressure in thechamber exceeds a pressure inside the membrane, the hole in the membranecloses and makes the shoe impermeable.
 7. The shoe sole of claim 1,wherein the inside air escapes until the inside pressure is compensatedby the pressure in the chamber.
 8. The shoe sole of claim 1, made by aprocess comprising the step of moulding the check valves and sole in onepiece in one moulding step.
 9. The shoe sole of claim 1, wherein themicrohole in the membrane of the valve is made by a process comprisingthe steps of moulding the sole and, after the moulding, mechanicallypiercing the membrane by means of needles or stings.
 10. The shoe soleof claim 1, wherein said check valves are inserted into said sole. 11.The shoe sole of claim 10, wherein the membrane and the chamber in saidinserted check valves are made in one piece inside the body of a tubularvalve.
 12. The shoe sole of claim 10, wherein said check valves are madeof materials having a different specific weight than that of the sole.13. The shoe sole of the claim 1, wherein the check valves of resilientmaterial are inserted into a leather sole.
 14. The shoe sole of claim 1,wherein the sole has one or more built-in parts of material withdifferent specific weight in which the check valves of resilientmaterial are inserted.
 15. The shoe sole of claim 1, wherein thechambers have tapered walls so as to facilitate the expulsion of debris.16. The shoe sole of claim 1, wherein there is provided a curved lipprojecting along a periphery of the concavity of the membrane andforming an upper chamber shaped as a dome which communicates with theinside of the shoe through a central hole at its top.
 17. The shoe soleof claim 16, wherein said central hole is aligned with the microhole inthe concave membrane.
 18. The shoe sole of claim 16, wherein said domesor igloos have the double function of massaging the foot and acting aspumps which cause the inner air to be forcibly expelled.
 19. The shoesole of claim 1, wherein spacing studs avoiding the aqua planing effectsare provided on the tread all around the hole in the chamber.
 20. Theshoe sole of claim 1, wherein the valves are distributed over areas ofthe sole selected from the group consisting of the whole sole and thosecorresponding to toes, arch and heel.
 21. The shoe sole of claim 1,wherein the check valves and sole comprise one piece formed from onemould.
 22. A shoe having a shoe sole, said shoe sole separating aninside of said shoe from an outside of said shoe, wherein in said sole aplurality of circular check valves are provided for discharging air fromthe inside of the shoe, each of said check valves comprising a circularmembrane having an upper central circular concavity, wherein a concavesurface of the concavity faces upward towards the inside of the shoe, alower central circular chamber, wherein a concave surface of the chamberfaces downwards towards a tread of the shoe, a diaphragm or screenseparating said upper concavity from said lower chamber, a piercedmicrohole in said diaphragm for connecting said upper concavity to saidlower chamber, wherein said shoe further comprises an air permeableinsole on top of said shoe sole, whereby a pressure exerted by a foot onthe insole causes the air contained within the shoe to pass from saidupper concavity to said lower chamber and to discharge to the outside ofthe shoe.
 23. A shoe sole according to claim 22, in which said upperconcavity is partially covered by a circular arcuated lip and has acentral opening for the passage of air towards said lower chamber,whereby said lip exerts a double action of increasing the expulsionforce of the air and exerting a massaging action on a user's foot. 24.The shoe sole according to claim 23, wherein said central opening isaligned with the microhole pierced in said diphragm.